The invention relates to the catalytic codimerization of norbornadiene and norbornene. Particularly the invention relates to the preparation of a codimer of norbornadiene and norbornene using a specified catalyst system. The resulting saturated codimer has utility as a component of high energy fuel. The norbornene hereinafter shall be referred to as NB.
High energy fuel, which is often referred to as a high density fuel, can be used in either jet or rocket propulsion. Jet propulsion includes a jet engine which can be used for a missile plane and others and includes the three basic types, i.e., ramjet, turbo-jet and pulse jet. The term rocket generally refers to a device containing its own oxygen or oxidizing agent.
Norbornadiene is also known as bicyclo-(2.2.1) heptadiene-2,5. A method of preparation is disclosed in U.S. Pat. No. 2,875,256 issued Feb. 24, 1959. Hereinafter, norbornadiene is referred to as NBD. The latter can be represented by either one of the following structural formulas: ##STR1##
NB is also known as bicyclo-(2.2.1) heptene-2. It can be prepared by reacting dicycopentadiene with ethylene at 200.degree. C. and 800 psi. The NB can be represented by either on of the following structural formulas: ##STR2##
NBD by itself will homodimerize to form an olefinic exo-exo hexacyclic dimer. Because of its olefinic nature the exo-exo hexacyclic dimer has a tendency to form gums and other like undesirable materials. The formation of such materials makes it undesirable as a fuel and to overcome the olefinic dimer is hydrogentated. The hydrogenated product is then useful as a component of high energy fuel.
A one step method with its advantages of reduced investments and operating costs for making the saturated exo-exo hexacyclic dimer of norbornadiene is desirable.